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THE    POISON    PARSNIP   0.  HEMLOCK 

A    PLANT    DEADLY  TO   LIVESTOCK  IN  NEVADA 

By  C.    E.    Fleming  and  IT.   P*    Peterson 
Univ,    of  Nevada  Bui.    ;,;100.  December   1920 


THE  UNIVERSITY  OF  NEVADA 
AGRICULTURAL  EXPERIMENT  STATION 


Bulletin  No.  100 


RENO,  NEVADA 


December,  1920 


To  diminish  suffering  and  loss  among  domestic  animals 

THE  POISON  PARSNIP  OR  WATER  HEMLOCK 

(Cicuta  occidentals) 

A  Plant  Deadly  to  Live  Stock  in  Nevada 

By 

C.  E.  FLEMING  and  N.  F.  PETERSON 
Of  the  Department  of  Range  Management 

Assisted  by 

M.  R.  MILLER 
Of  the  Department  of  Chemistry 

and 

DR.  L.  H.  WRIGHT  and  DR.  R.  C.  LOUCK 
Of  the  Department  of  Veterinary  Science 


PUBLISHED  BY  THE  UNIVERSITY  OF  NEVADA 
RENO,  NEVADA 


I54 


Printed  at  the 

STATE  PRINTING  OFFICE— JOE  FARNSWORTH,  SUPERINTENDENT 
CARSON  CITY,  NEVADA 


NEVADA  AGRICULTURAL  EXPERIMENT  STATION 


BOARD  OF  CONTROL 

Hon.  G.F.TALBOT  (1931)          .        .        .        .        .        .        ,        .        .  Reno 

Hon.  B.  F.  CUBLEB  ( 1921 )          .        .       v        .        .        .        .        .       .  *  Elko 

Hon.  WALTEB  E.  PBATT  (1925)          .        .        v       ,        .      ;.        .        .  Reno 

Hon.  Mrs.  W.  H.  HOOD  (1927)           . Reno 

Hon.  MILES  E.NOBTH  (1929)    .        l.  "      .  '      .        .      •.        .        ;.     ,   .  Reno 

OFFICERS 

WALTEB  E.  CLABK,  Ph.D.  ..-.,»       ,..,,,  .  .  President  of  University 

CABOLYN  BECKWITH          .        ,  .-  ,        .        .  .  >  .        .        .   Secretary 

CHABLES  H.  GOBMAN         .        .        .        .        .  .  .  .        .       Comptroller 

STAFF 
SAMUEL  B.  DOTEN,  M.  A.    .;       .        ,*  .      .        .        .       Director  and  Entomologist 

F.  L.  BIXBY,  C.E Irrigation 

(In  cooperation  with  Bureau  of  Public  Roads,  U.  S.D.  A.) 

GEO.  HABDMAN,  M.S. Assistant  in  Irrigation 

CHABLES  E.  FLEMING,  B.S. A.    .      ^.-—  r~  ~        .        .  Range  Management 

EDWABD  RECOBDS,V.M.D. Veterinarian 

LYMAN  R.VAWTEB,  D.V.M.        .     ,.., Pathologist 

MADGE  L.  FINK,  B.A.          .        .        .        .        Secretary  to  Veterinary  Department 

M.  R.  MILLEB,  B.S Chemist 

MABTHA  RYAN  .        .        .        .        .        .       Librarian  and  Secretary  to  Director 


Ajgpic, -Forestry. 


487681 


Poison  Parsnip   (Cicuta  occidentalis).    The  Most  Dangerous  Stage  of  Growth. 


THE    PURPOSE    OF    THIS    BULLETIN 


While  for  more  than  half  a  century  in  Nevada  the  plant  known  here 
as  poison  parsnip  has  been  recognized  as  a  poisonous  plant,  there  has 
been  concerning  it  a  good  deal  of  confused  opinion. 

Even  among  trained  scientists  there  is  no  agreement.  One  writer 
states  that  the  tops  are  poisonous ;  another  that  41  pounds  of  the  roots 
were  fed  within  two  weeks  to  a  sheep  without  causing  serious  illness. 
Some  writers  assert  that  the  roots  are  much  less  poisonous  at  one  time 
of  year  than  at  another ;  others,  that  cattle  and  horses  are  poisoned,  but 
not  sheep  or  goats.  To  clear  away  this  confusion  and  to  gain  exact 
information  which  would  be  of  service  to  Nevada  stockmen,  several 
series  of  feeding  tests  were  undertaken  at  the  University. 

Evidently,  the  actual  feeding  of  roots  and  tops  to  live  stock  is  the 
best  possible  method  of  gaining  exact  information  about  the  amount 
required  to  kill  an  animal,  the  part  of  the  plant  which  is  poisonous,  and 
the  time  of  year  when  it  is  dangerous.  For  example,  we  cannot  reach 
a  safe  conclusion  concerning  the  deadly  dose  for  a  sheep  by  feeding  the 
plant  to  a  rabbit  or  a  guinea  pig.  Chemical  analyses,  however,  throw 
much  light  upon  the  nature  of  the  active  poisonous  principles  in  the 
plant. 

The  series  of  feeding  tests  summarized  in  this  bulletin  cleared  away 
much  of  the  previous  confusion  of  opinion,  and  showed  what  part  of 
the  plant  is  deadly  and  also  how  poisoning  may  readily  be  prevented. 

It  is  clear  that  in  the  long  run  studies  of  this  character  will  diminish 
suffering  and  loss  among  our  domestic  animals. 

S.  B.  DOTEN, 

Director,  Nevada  Agricultural  Experiment  Station. 
UNIVERSITY  OF  NEVADA,  December  1,  1920. 


figure  1.  Flowers  of  Poison  Parsnip  (Water  Hemlock).  The  flowers, 
like  those  of  the  common  parsnip,  are  borne  in  little  clusters  on 
slender  stems,  which  radiate  from  the  end  of  the  flower  stalk  like  the 
ribs  of  an  umbrella. 


SECTION    I 

Poison  Parsnip  (Water  Hemlock)  as  a  Plant  Deadly  to 
Live  Stock  in  Nevada 


SUMMARY 

(1)  The  poison  parsnip  or  water  hemlock  is  a  poisonous  weed  com- 
monly found  along  ditch  banks  and  in  wet  pasture  lands  throughout 
the  larger  part  of  Nevada. 

(2)  The  leaves  look  somewhat  like  those  of  celery  or  the  common 
parsnip.     They  are  dark-green  and  glossy.     The  plant  sends  up  long 
branching  stems  from  two  to  even  five  or  six  feet  high,  bearing  numer- 
ous flattened  clusters  of  tiny  white  flowers. 

(3)  The  rootstock  is  thick  and  fleshy  with  numerous  branches  some- 
times as  thick  as  a  man 's  thumb.    The  main  root,  rootstock,  has  numer- 
ous empty  spaces  in  the  middle  with  cross-partitions.    When  it  is  cut 
little  drops  of  a  yellow  poisonous  sap  ooze  out. 

(4)  In  late*  summer  the  seeds  fall  into  the  water  and  are  carried 
away  for  long  distances,  finally  being  washed  out  upon  wet  pasture 
land  or  else  lodging  against  the  bank  of  the  ditch,  producing  new 
plants. 

(5)  A  long  and  complete  series  of  experiments,  1918—1920,  conducted 
by  the  Nevada  Agricultural  Experiment  Station  showed  that  (a)  the 
leaves  and  stems  are  not  poisonous  in  summer  or  autumn,  and  large 
quantities  might  then  be  eaten  by  either  sheep  or  cattle  without  harm  ; 
(b)  the  roots  are  deadly  throughout  the  year,  the  old  rootstocks  being 
more  poisonous  than  the  new;   (c)  the  first  green  leaves  and  stems 
coming  up  from  the  ground  in  the  spring  are  deadly,  almost  as  much 
so  as  the  roots  themselves;   (d)  under  ordinary  conditions  very  few 
animals  ever  get  the  roots  in  summer  and  autumn.    Frost  and  ice  in 
winter  frequently  loosen  and  heave  up  the  roots.    They  may  then  be 
pulled  and  eaten  in  the  spring  by  animals  attracted  by  the  new  green 
growth. 

(6)  The  greatest  danger  comes  from  the  tender  green  shoots  in  the 
spring.     They  are  apt  to  show  up  strongly  along  ditches  before  the 
grass  begins  to  grow,  and  may  then  be  eaten  greedily  by  animals 
hungry  for  green  feed. 

(7)  Losses  from  poison  parsnip  (water  hemlock)  are  readily  pre- 
vented by  keeping  stock  away  from  places  where  the  plant  grows  in 
the  spring,  until  other  green  feed  is  making  a  good  showing. 

(8)  Along  ditch  banks  the  poison  parsnip  may  easily  be  grubbed  out. 
It  appears  to  be  unnecessary  to  dig  the  whole  root,  as  apparently  if  the 
top  of  the  rootstock  is  cut  off,  no  new  shoots  will  be  sent  up  from  the 
remainder.     Roots  which  have  been  dug  should  be  dried  in  a  place 
where  cattle  cannot  get  at  them  and  then  burned ;  for  even  when  dead 
and  dry  they  are  still  extremely  poisonous. 

(9)  This  bulletin  contains  a  detailed  report  of  feeding  experiments 
on  which  the  above  conclusions  are  based. 


Figure  2.  Flowers  and  Leaves  of  the  Poison  Parsnip.  This  is 
growing  in  the  midst  of  a  tangle  of  other  vegetation  in 
a  swampy  meadow. 


From  the  days  of  the  earliest  settlements  in  Nevada  the  poison 
parsnip  (water  hemlock)  has  been  known  as  a  poisonous  plant.  Long; 
before  the  white  people  came  into  the  country  its  properties  were  known 
to  the  Indians,  who  used  it  as  a  means  of  suicide.  The  roots  and  the 
earliest  green  growth  are  violently  poisonous  to  all  kinds  of  live  stock 
and  every  year  cause  losses  of  cattle,  horses,  and  sheep.  The  greatest 
losses  are  of  cattle,  perhaps  largely  because  they  are  more  frequently 
pastured  where  the  plant  is  abundant. 

Common  Names  of  Water  Hemlock. 

In  Nevada,  as  in  other  Western  States,  this  poisonous  plant  is  usually 
called  Poison  Parsnip  or  Wild  Parsnip.  In  some  other  States  it  is 


Figure  3.  The  Leaf  of  the  Poison  Parsnip.  The  leaflets 
grow  in  little  groups  by  twos  and  threes,  and  the  edge  of 
each  leaflet  is  sharply  saw-toothed. 

often  called  Cow-bane.  Perhaps  the  best  common  name  is  Water 
Hemlock.  The  scientific  name  of  the  kind  found  in  Nevada  is  Cicuta 
occidentalis.  Throughout  the  northern  half  of  the  world  there  are 
many  other  kinds  of  Cicuta,  all  of  which  contain  deadly  poisons. 

Description  of  Plant. 

The  poison  parsnip  belongs  to  the  parsley  family.     Mature  plants 
are  from  two  to  six  feet  high.    The  largest  leaves  are  at  the  bases  of  the 


8  

plants  and  are  twice  branched  (see  Figures  2  and  3).  The  stem  is 
smooth,  green,  and  hollow,  except  at  the  nodes  or  joints  where  the 
leaves  are  attached.  This  hollow  is  formed  by  the  breaking  down  of 
the  pith,  and  very  young  stems  may  still  be  solid.  The  flower  clusters 
are  broad  and  flat  and  resemble  those  of  parsnips  or  carrots.  The 
flowers  are  small  and  inconspicuous,  greenish-white  in  color.  Flowers 
and  flower  clusters  are  well  shown  in  Figures  1  and  2. 

The  lower  underground  part  of  the  stem  is  thickened  and  fleshy,  with 
a  series  of  cross-partitions,  which  divide  the  interior  into  small  short 
chambers,  as  shown  in  Figure  4.  The  hollows  between  these  partitions 
are  formed  like  the  hollow  in  the  rest  of  the  stem — that  is,  by  the 


Figure  4.  Boot  and  Rootstock  of  the  Poison  Parsnip.  The  full- 
grown  rootstock  is  divided  by  thin  partitions  into  a  number 
of  shallow  chambers. 

breaking  down  of  the  pith ;  and  they  may  not'  be  found  in  very  young 
roots.  Attached  to  this  thickened  tuberous  central  portion  are  a  num- 
ber of  thick  fleshy  roots  with  some  ordinary  root-fibers. 

When  the  tuber  or  the  roots  are  cut,  a  reddish  or  yellowish  sirupy 
liquid  oozes  out  on  the  cut  surface.  This  is  cicutoxin,  the  poisonous 
principle  of  the  plant. 

How  to  Distinguish  the  Poison  Parsnip  from  Other  Plants. 

Several  other  plants  belonging  to  the  parsley  family  resemble  the 
poison  parsnip  so  much  that  they  may  be  mistaken  for  it  if  the  tops 


9  

alone  are  examined.  However,  they  may  all  be  distinguished  easily  if 
the  underground  parts  are  dug.  Only  a  few  of  the  others  have  an 
underground  stem  with  cross-partitions ;  and  in  these  it  is  not  thick  and 
fleshy  and  has  no  fleshy  roots  like  those  of  the  poison  parsnip,  and  no 
cicutoxin  appears  when  the  underground  stem  is  cut. 

The  common  field  parsnip  has  a  fleshy  root;  but  it  lacks  the  open 
spaces,  the  cross-partitions,  and  the  yellow  cicutoxin.  Both  the  field 
parsnip  and  the  poison  parsnip  have  a  peculiar  odor  which  is  lacking 
in  other  plants  of  much  the  same  appearance. 

The  stems  and  leaves  of  the  poison  parsnip  are  coarse,  the  flower  is 
white,  and  the  whole  plant  has  a  strong  unpleasant  odor  when  crushed. 
On  the  whole,  it  is  easy  to  tell  the  roots  of  the  poison  parsnip  from  any 
of  the  others  by :  (1)  the  cross-partitions  of  the  rootstock ;  (2)  the  rank 
parsnip  smell;  (3)  the  oily  yellow  drops  of  deadly  cicutoxin  which 
ooze  out  when  the  rootstock  is  cut.  If  a  root  shows  all  three  of  these 


Figure  5.  Leaves  of  Water  Parsnip  (on  left)  and  Water  Hemlock, 
or  Poison  Parsnip.  The  principal  difference  appears  to  be  in 
the  fact  that  the  leaflets  of  water  parsnip,  a  harmless  plant, 
grow  singly,  while  those  of  water  hemlock  grow  in  little  groups 
of  two  or  three  each. 

characters,  one  may  be  sure  that  it  is  the  root  of  the  poison  parsnip 
(water  hemlock) . 

In  Nevada  many  related  plants  belonging  to  the  parsnip  family 
grow  in  dry  soil,  but  the  poison  parsnip  is  never  found  except  in  wet 
places.  There  is  another  plant  called  water  parsnip  (Sium)  which 
grows  in  similar  places  and  is  often  associated  with  the  water  hemlock. 
It  can  be  distinguished  by  the  less  divided  leaf,  shown  in  Figure  5. 

Where  It  Grows. 

The  poison  parsnip  or  water  hemlock  grows  in  wet,  marshy  soil  or  in 
shallow  water.  It  is  common  along  streams  and  around  ponds,  and  in 
or  along  ditches.  In  Nevada  it  is  most  commonly  found  along  the 
edges  of  irrigation  ditches  and  scattered  over  wet  meadows  and 
pastures.  It  does  not  usually  occur  throughout  such  pastures  and 
meadows,  but  is  limited  to  very  wet  areas  and  to  the  ditch  banks. 


10 


Methods  of  Reproduction  and  Spread. 

The  plant  produces  a  great  amount  of  seed  which  is  carried  by  the 
irrigation  water  to  new  fields  and  ditches.  Small  plants  are  sometimes 
washed  out  and  carried  to  a  distance  by  the  water,  but  it  is  the  seed 
falling  on  the  water  which  is  the  important  means  of  spread. 

The  seedlings  do  not  bloom  nor  produce  seeds  the  first  year;  and 
it  may  take  the  plant  several  seasons  to  develop  a  tuber  large  enough  to 
send  up  a  flowering  stem.  The  young  plants  do  not  produce  an  erect 
stem,  but  only  a  bunch  of  leaves.  Each  year  the  old  tuber  dies  in  the 
fall;  but  before  this  happens  it  has  given  rise  to  one  or  more  new 
tubers  which  live  through  the  winter  and  begin  growth  again  very 
early  the  next  spring.  When  more  than  one  new  tuber  is  formed,  this 


Figure  6.  Roots  and  Early  Spring  Growth  of  the  Poison  Parsnip 
(Water  Hemlock).  Both  the  rootstock  and  the  fleshy  roots  contain 
the  deadly  cicutoxin. 

results  in  a  local  increase  in  the  number  of  plants.  For  this  reason  the 
poison  parsnip  plants  often  grow  in  clusters  which  all  originated  from 
a  single  seed. 

When  the  new  tuber  is  first  formed  it  contains  little  or  no  cicutoxin, 
but  as  it  grows  older  the  amount  increases  until  it  becomes  as  poisonous 
as  the  old  ones.  This  difference  between  the  new  tubers  and  the  old  is 
probably  what  has  led  some  writers  to  conclude  that  the  plant  is  less 
poisonous  at  certain  times  in  the  year.  The  old  decaying  tubers  retain 
most  of  their  cicutoxin,  the  poisonous  principle,  and  are  still  poisonous 
when  almost  completely  decayed. 


11 

Poisonous  Principle. 

The  poisonous  principle,  as  has  been  already  stated,  is  called  cicu- 
toxin.  This  substance  is  found  principally  in  the  tuberous  under- 
ground parts  of  the  plant,  i.  e.,  in  the  rootstock  and  in  the  tuberous 
roots.  When  the  little  green  shoots  first  come  up  in  the  spring  they 
contain  considerable  amounts  and  are  almost  as  poisonous  as  the  tubers. 
Later  only  very  small  amounts  are  present  in  the  lower  part  of  the 
stem  and  in  the  lower  leaf  stalks.  The  chemistry  of  cicutoxin  is  fully 
discussed  by  Dr.  C.  A.  Jacobson  in  Bulletin  No.  81  of  this  Station. 

Time  of  Year  When  Most  Dangerous. 

The  early  spring  while  the  leaves  are  still  poisonous  is  the  time  when 
the  plant  is  the  most  dangerous.  At  this  time  also  the  tubers  may  be 
trampled  or  pulled  out  of  the  ground  and  eaten;  but  later  they 
develop  fibrous  roots  and  are  so  anchored  by  these  and  by  the  roots  of 
other  plants,  that  it  is  almost  impossible  for  grazing  animals  to  pull 
them.  In  the  early  spring  in  some  soils  the  tubers  are  loosened  and 
often  stand  partly  above  the  surface  of  the  ground,  heaved  up  by 
winter  frost  and  ice.  The  first  leaves  grow  rapidly  because  they  are 
nourished  by  food  stored  in  the  tuber ;  they  make  tempting  feed  before 
other  plants  have  made  much  growth  (see  frontispiece  and  Figure  6). 

Purpose  of  the  Experimental  Feedings. 

At  the  time  when  our  feeding  tests  were  undertaken,  although  the 
plant  had  long  been  considered  poisonous,  only  a  few  experiments  had 
been  made  to  determine  exactly  what  parts  of  the  plant  are  poisonous 
and  how  much  of  each  part  it  will  take  to  make  an  animal  sick  or  to 
cause  death.  Moreover,  different  experimenters  had  obtained  very 
different  results. 

Because  of  this  lack  of  exact  information  the  Nevada  Station  has 
made  a  long  series  of  experimental  feedings  of  various  parts  of  the 
plant  to  sheep,  cattle,  and  horses.  The  old  tubers  were  fed  at  different 
times  during  the  growing  season;  the  new  tubers,  when  they  had 
formed  in  midsummer;  the  leaves,  when  they  first  appeared  in  the 
spring,  while  the  older  tops  were  fed  at  different  times  during  the 
summer.  As  all  of  the  Nevada  material  was  collected  near  Reno,  and 
because  it  seemed  possible  that  differences  of  climate  and  soil  might 
make  a  difference  in  the  poisonous  quality  of  the  plant,  a  few  other 
feedings  were  made  with  material  which  was  collected  in  Nebraska. 
The  results  of  all  of  these  feedings  follow. 

TABLE  No.  I 

POISON  PARSNIP  (WATER  HEMLOCK).    FRESHLY  GATHERED  OLD  TUBERS 

FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

6  

65 

5-29-18 

3:45  p.  m. 

i 

Negative 

29 

65 

5-30-18 

3:00  p.  m. 

1 

Negative 

33  

90 

8-20-18 

2:15  p.  m. 

Negative 

8 

72 

8-30-18 

3:08  p.  m. 

j 

Negative 

34 

97 

8-20-18 

2-35  p.  m 

li 

Negative 

36  

102 

8-20-  18 

2:50  p.  m. 

2 

Negative 

6.  — 
16 

65 
70 

5-30-18 
5-30-18 

3:05  p.  m. 
3'00  p  m 

2 

2 

4:30  p.  m 
3*25  p   m 

6:00  p.  m. 
4  '07  p.  m. 

Recovery 
Death 

28. 

78 

8-20-18 

3:50  p.  m. 

2 

4:45  p.  m 

5:10  p.  m. 

..Death 

11 

73 

5-30-18 

2*55  p  m 

3 

3-35  p.  m 

4:21  p.  m. 

Death 

7  

71 

5-30-18 

3:14  p.m. 

3 

3:30  p.  m 

4:02  p.  m. 

...Death. 

32 

80 

8-20-18 

4:10  p.  m. 

3 

(?) 

Before  7:15  p.  m. 

.  —  Death 

13 

69 

5-30-18 

2*58  p  m 

4 

3-25  p  m. 

4  '36  p.  m. 

Death 

23  . 

78 

5-28-18 

4:15  p.  m. 

5i"0 

4:35  p.  m. 

5:28  p.  m. 

Death 

12 


Feeding  Freshly  Dug  Old  Tubers  to  Sheep. 

During  the  seasons  of  1918  and  1919,  fourteen  feedings  of  fresh  old 
tubers  were  made,  the  results  of  which  are  summarized  in  Table  No.  I. 

Amounts  from  \  to  \\  ounces  gave  negative  results.  Four  two- 
ounce  feedings  were  made ;  one  caused  no  symptoms,  one  made  a  sheep 
sick,  but  it  recovered,  while  both  the  other  two  caused  death.  The  sheep 
that  was  not  made  sick  was  larger  than  the  others.  All  feedings  of 
three  ounces  and  over  caused  death.  Thus,  any  amount  of  the  tubers 
above  two  ounces  when  eaten  by  ordinary  range  ewes  will  probably 
cause  death.  That  is,  if  a  ewe  eats  more  than  J  of  a  pound,  death  is 
likely  to  follow. 

Feeding  Dried  Old  Tubers  to  Sheep. 

The  old  tubers  were  dug  and  allowed  to  dry  in  the  air.  The  results 
of  feeding  air-dried  tubers  are  shown  in  Table  No.  II. 

TABLE  No.  II 
POISON  PARSNIP  (WATER  HEMLOCK).    AIR-DRIED  OLD  TUBERS  FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

25  

77 

7-5-18 

10:35  a.m. 

| 

11:55  a.  m. 

12:24  p.  m. 

Death 

We  made  only  one  feeding  of  the  dried  tubers  to  sheep.  The  result 
showed  conclusively  that  the  air-dried  tubers  are  deadly  and  made 
further  tests  unnecessary. 

Eighteen  pounds  of  old  tubers  were  air  dried  to  2.9  pounds,  or  only 
Ve  of  the  original  weight.  A  half  ounce,  1/32  of  a  pound,  of  this  dry 
material  was  fed.  This  is  equivalent  to  about  three  ounces  of  the  fresh 
tubers.  The  result  was  death,  the  animal  exhibiting  typical  water 
hemlock  poisoning  symptoms. 

This  one  feeding  indicated  (1)  that  there  is  little  if  any  immediate 
loss  of  the  poisonous  principle  upon  dr}ring,  and  (2)  that  grubbed  roots 
are  extremely  dangerous  to  live  stock  and  should  be  so  disposed  of  that 
there  is  no  chance  of  animals  eating  them. 

Feeding  New  (Young)  Tubers  to  Sheep. 

Table  No.  Ill  summarizes  the  feeding  of  new  tubers  to  sheep : 

TABLE  III 

POISON  PARSNIP  (WATER  HEMLOCK).    FUESHLY  GATHERED  NEW  TUBERS 

FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

35  — 

Ill 

8-20-18 

2:23  p.  m. 

2 

.    Negative 

29  

65 

8-20-18 

3:40  p.  m. 

2 

Negative 

36  

110 

8-24-18 

11:40  a.m. 

4 

-.  Negative 

47 

60 

8-  1-19 

11:00  a.m. 

5 

(?) 

Death 

33  

90 

8-20-18 

9:00  a.  m. 

6 

Negative 

36  

110 

8-27-18 

9:00  a.  m. 

8 

9:35  a.  m. 

10:32  a.  m. 

Death 

Five  feedings  of  freshly  dug  new  tubers  were  made  in  1918 ;  and 
amounts  from  two  to  six  ounces,  £  to  J  of  a  pound,  produced  no 
symptoms,  while  eight  ounces,  \  pound,  caused  death.  A  single  feed- 
ing of  five  ounces  made  in  August,  1919,  caused  death.  It  would  appear 
from  these  feedings  that  it  takes  from  two  to  four  times  as  much  of 


13 


the  new  tubers  to  kill  as  of  the  old.  It  seems  probable  that  the  very 
young  tubers  are  only  slightly  poisonous,  becoming  more  so  later  in 
the  season,  until,  when  fully  matured,  they  are  as  poisonous  as  the  old 
ones. 

Feeding  Tubers  of  Water  Hemlock  from  Nebraska. 

The  material  fed  to  sheep  in  Table  No.  IV  was  collected  in  Nebraska 
and  fed  in  Nevada. 

TABLE  No.  IV 

POISON  PABSNIP  (WATER  HEMLOCK).    WILTED  TUBERS  FROM  NEBRASKA 

FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

76    - 

81 

7-13-20 

10:00  a.  m. 

1 

Negative 

77 

88 

7-13-20 

10-00  a.  m. 

1 

Negative 

74  

88 

7-13-20 

10:10  a.  m. 

li 

Negative 

69 

74 

7-13-20 

10:10  a.  m. 

li 

Negative 

28 

59 

7-13-20 

10-20  a  m. 

2 

120  

102 

7-14-20 

8:15  a.  m. 

2i 

77 

83 

7-14-20 

8-25  a.  m. 

3 

Negative 

10  

8 

89 
98 

7-14-20 
7-14-20 

10:20  a.  m. 
2:45  p.  m. 

4 
4 

1:00  p.  m. 

3:00  p.  m. 

Recovery 

28  

58 

7-15-20 

8:45  a.  m. 

4 

Negative 

The  Nebraska  material  was  partly  dry,  and  had  lost  about  half  its 
weight,  so  that  in  Table  IV  the  amount  fed  is  doubled. 

From  the  results  it  would  appear  that  the  Nebraska  rootstocks  were 
less  poisonous  than  those  from  Nevada.  As  seen  by  Table  No.  I,  two 
ounces  of  the  Nevada  material,  when  fed  fresh,  usually  caused  serious 
poisoning  or  death,  while  it  took  four  ounces  of  the  Nebraska  material 
to  cause  symptoms.  These  feedings  seem  to  show  that  the  water  hem- 
lock is  less  dangerous  in  some  parts  of  the  country  than  in  others. 

Feeding  Young  Leaves  to  Sheep. 

More  losses  of  stock  from  water  hemlock  poisoning  occur  in  the  early 
spring  than  at  any  other  season,  and  it  is  by  no  means  clear  that  such 
losses  are  always  due  to  the  eating  of  pulled  tubers.  For  this  reason 
it  seemed  probable  that  the  green  shoots  of  the  plant  are  poisonous 
when  they  first  appear  in  the  spring.  Table  No.  V  summarizes  the 
results  of  feeding  young  leaves  to  sheep : 

TABLE  No.  V 
POISON  PARSNIP  (WATER  HEMLOCK).    YOUNG  TOPS  FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed.  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

48 

91 

2-3-20 

10-15  a  m 

6 

10-40  a  m 

11-10  a  m 

Death 

37 

87 

2-5-20 

9-50  a  m 

1 

Negative 

56 

120 

2-5-20 

2*10  p  m 

2 

Negative 

37 

90 

2-6-20 

8*35  a  m 

3 

11*15  a  m 

Death 

64 

85 

4-2-20 

l-30p  m 

3 

.     .  Negative 

64 

85 

4-3-20 

10:30  a.  m. 

4 

..  Negative 

64 

85 

4-9-20 

11-08  a  m 

8 

12-45  p  m 

2:00  p.  m. 

Death 

68 

101 

5-5-20 

11-50  a  m 

16 

Negative 

68— 

101 

5-5-20 

3:30  p.  m. 

40 

.-  Negative 

Fed  green  parts  of  leaves  only: 

101  i      5-6-20  I    9:25  a.  m. 


10:00  a.  m. 


Slight  trembling 

only  symptom   Recovery 


Ten  feedings  were  made.     In  the  series  of  feedings  made  early  in 


14  

February  one  and  two  ounces  produced  no  symptoms,  while  three 
ounces  caused  death.  The  leaves  were  then  about  two  to  three  inches 
tall  and  the  leaflets  were  not  yet  unfolded.  The  results  indicate  that 
the  leaves  at  this  stage  of  development  are  almost  as  deadly  as  the 
tubers. 

In  April  three  feedings  were  made.     Feedings  of  three  and  four 
ounces  gave  negative  results,  while  eight  ounces  caused  death.     The 


Figure  7.  The  Poison  Parsnip  Growing  in  a  Wet  Meadow.  In  such 
locations  the  plant  is  easily  grubbed  out,  and  the  cost  of  a  single 
poisoned  animal  would  more  than  pay  for  the  labor  required  to 
clear  a  large  area. 

leaflets  were  now  beginning  to  unfold  and  the  leaves  were  becoming 
less  toxic. 

Early  in  May  two  feedings  were  made  of  leaves  from  which  all  parts 
which  had  not  turned  green  were  removed.  One  feeding  was  of  one 
pound,  and  the  other  of  2J  pounds.  No  symptoms  were  produced  from 
either  feeding.  The  following  day  the  white  and  yellow  parts,  amount- 


15 


ing  to  seven  ounces,  less  than  half  a  pound,  which  had  been  discarded 
from  the  material  used  in  the  above  feedings,  were  fed  to  the  same 
sheep.  About  half  an  hour  after  feeding,  it  had  a  slight  nervous 
trembling,  resembling  the  first  symptoms  exhibited  when  an  animal 
becomes  poisoned  with  this  plant.  No  other  symptoms  developed.  It 
appears  therefore  from  this  series  of  feedings  that  as  the  leaves  expand 
and  become  green  they  cease  to  be  poisonous. 

The  growth  in  February  was  due  to  abnormally  warm  weather ;  and 
ordinarily  the  first  green  shoots  would  not  appear  till  some  weeks  later 
in  the  season. 

Such  early  spring  growth  is  very  tempting,  being  about  the  only 
green  feed  available,  and  is  highly  dangerous  to  live  stock. 

Feeding  Older  Tops  to  Sheep. 

Table  No.  VI  gives  results  of  feeding  older  tops  to  sheep. 

TABLE  No.  VI 
POISON  PARSNIP  (WATER  HEMLOCK).     THE  OLD  GREEN  PLANT  FED  TO  SHEEP 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  Ibs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

6 

65 

5-28-18 

4*25  p.  rn 

. 

Negative 

29  

65 

5-29-18 

3:40  p.  m 

i 

..  Negative 

7 

71 

5-29-18 

4'20p.  m 

1 

Negative 

28 

65 

6-15-18 

10-00  a  m 

1 

Negative 

24 

67 

5-30-18 

11:45  a.  m 

2 

Negative 

4 

87 

6-18-18 

3'00p  m 

6 

Negative 

32.- 

85 

7-26-18 

10:30  a.  m 

10 

.-  Negative 

7-27-18 

1-00  p.  m 

7 

Negative 

7-28-18 

8:30  a.  m 

10 

_.  Negative 

7-29-18 

7:30-11:30  a.  m 

6 

Negative 

4-30p  m 

2 

Negative 

75,  78.- 

80  ea. 

6-21-20 

4 

..  Negative 

6-22-20 

84 

._  Negative 

6-23-20 

8 

—  Negative 

6-28-20 

7 

Negative 

As  will  be  seen  from  the  above  table  single  feedings  up  to  six  pounds 
were  made  without  producing  any  symptoms.  A  sheep  was  fed 
amounts  varying  from  7  to  10  pounds  daily  for  four  days,  making  a 
total  of  35  pounds,  without  showing  any  symptoms.  Two  sheep  were 
fed  22  pounds  in  four  days  without  showing  any  symptoms. 

This  shows  that  the  older  tops  are  practically,  if  not  entirely,  non- 
poisonous,  and  that  there  is  no  danger  in  feeding  them,  or  allowing 
sheep  to  graze  upon  them,  or  in  feeding  hay  containing  water  hemlock 
tops. 

Feeding  Old  Water  Hemlock  Tubers  to  Cattle. 

Table  No.  VII  shows  the  results  of  feeding  fully  matured  tubers 

to  cattle. 

TABLE  No.  VII 

POISON  PARSNIP  (WATER  HEMLOCK).     OLD  TUBERS  FED  TO  CATTLE 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

739 

985 

6-15-18 

10-00  a  m 

4 

Negative 

739 

985 

6-19-18 

g 

Negative 

739 

985 

6-21-18 

9-45  a.  m 

12 

10-50  a  m 

11:00  a.  m. 

Death 

A  cow  was  fed  four  ounces  without  producing  any  symptoms,  and 
four  days  later  eight  ounces  were  fed  with  no  effect.    Two  days  later 


16 


she  was  fed  12  ounces,  which  caused  death.  The  poisonous  dose  for  a 
cow  of  nearly  1,000  pounds  weight  would  seem  to  be  somewhere 
between  £  and  -J  of  a  pound  of  the  freshly  gathered  old  tubers. 

Feeding  Old  Water  Hemlock  Tops  to  Cattle. 

Table  No.  VIII  gives  the  results  of  feeding  old  water  hemlock  tops 
to  cattle. 

TABLE  No.  VIII 

POISON  PARSNIP  (WATER  HEMLOCK).    THE  OLD  GREEN  PLANT  WITHOUT  ROOTS 

FED  TO  CATTLE 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  Ibs. 

Time  symptoms 
appeared 

Time  of  death 
or  recovery 

Final  result 

739 

985 

5-29-18 

4*30  p.  m. 

2* 

Negative 

5-30-18 

9:30  a.  m. 

Negative 

11:30  a.  m. 

5i 

Negative 

3:15  p.  m. 

li 

Negative 

5:00  p.  m. 

6 

Negative 

5-31-18 

9-30  a  m. 

el 

Negative 

6-  1-18 

9:30  a.  m. 

10 

Negative 

9'45  a.  m. 

9 

Negative 

11:15  a.m. 

9 

Negative 

6-  4-18 

3:10  p.  m. 

22* 

Negative 

3:35  p.  m. 

18| 

Negative 

15 

235 

6-20-20 

Negative 

6-21-20 

g 

Negative 

6-22-20 

8i 

Negative 

6-23-20 

12 

Negative 



During  four  days  a  cow  was  fed  46  pounds,  eating  as  much  as  28 
pounds  in  a  single  day.  Later  she  ate  41  pounds  in  an  afternoon 
without  any  symptoms. 

A  calf  was  fed  33J  pounds  in  four  days,  eating  as  much  as  12  pounds 
in  one  day,  without  showing  any  symptoms.  This  shows,  as  did  the 
feeding  of  tops  to  sheep,  that  the  old  tops  are  not  dangerous. 

Feeding  Old  Water  Hemlock  Tubers  to  Horses. 

Table  No.  IX  gives  results  of  feeding  old  tubers  to  horses. 

TABLE  No.  IX 

POISON  PARSNIP  (WATER  HEMLOCK).    FRESHLY  GATHERED  OLD  TUBERS 
FED  TO  HORSES 


Animal 
No. 

Weight 
Ibs. 

Date  fed 

Time  fed 

Amount 
fed,  ozs. 

Time  symptoms 
appeared 

Time  of  death  or  recovery 

8.  

865 

5-26-19 

2:05  p.  m. 

15 

2*50  p.  m 

Shot  at  3*22  p  m 

2  

990 

5-27-19 

10:15  a.  m. 

8 

10-45  a  m 

Shot  at  10*54  a  m 

Only  two  horses  were  fed — one  received  eight  ounces,  J  of  a  pound ; 
and  the  other  15  ounces,  nearly  a  pound.  Both  were  made  sick  and 
would  have  died.  There  w^s  no  hope  for  their  recovery  and  they  were 
in  such  agony  that  they  were  shot  for  humane  reasons.  The  poisonous 
dose  appears  to  be  less  for  a  horse  than  for  a  cow  of  about  the  same 
weight  (see  Figure  8). 

Time  Required  for  Symptoms  to  Appear. 

With  sheep  it  took  from  16  to  75  minutes  for  symptoms  to  appear. 
In  eight  cases  the  average  time  was  39  minutes.  The  two  cases  in 
which  the  earliest  symptoms  were  not  observed  would  probably  have 
increased  the  average  a  little.  In  the  cow  it  took  about  an  hour,  and  in 


17 


M 

••• 


Figure  8.   A  Horse  Fatally  Poisoned 
by  the  Poison  Parsnip. 


18  

the  two  horses  30  and  45  minutes.     Cicutoxin  is  evidently  a  poison 
which  is  rapidly  taken  up  by  the  system  and  which  acts  quickly. 

Symptoms. 

Usually  the  first  symptom  noticed  was  a  twitching  of  the  muscles; 
and  often  a  quivering  of  the  lips  and  nose  and  a  pronounced  uneasi- 
ness. This  was  soon  followed  by  a  series  of  spasms,  during  which  there 
was  convulsive  champing  of  the  jaws  and  grating  of  the  teeth  and  a 
bending  backward  of  the  head  and  neck.  In  the  tests  the  cattle  and 
sheep  usually  went  down  with  the  first  severe  spasm  and  never  got  up 
again ;  while  the  horses  stayed  on  their  feet  during  some  of  the  spasms 
and  would  get  up  again  after  going  down.  While  down,  there  would  be 
a  series  of  spasms  at  intervals  of  varying  length.  During  these  inter- 
vals the  animal  would  sometimes  appear  to  be  recovering. 

During  the  spasms  there  was  always  a  very  rapid  kicking  or1  run- 
ning movement  of  the  legs,  often  rolling  of  the  eyes,  groaning,  grating 
of  the  teeth,  and  movements  of  the  jaws.  The  head  was  often  drawn 
back,  the  legs  stiffened ;  and  frothing  at  the  mouth  was  often  noticed. 
Sometimes  the  animal  would  groan  from  pain  while  lying  still. 

In  the  one  sheep*  that  recovered  there  was  almost  constant  dribbling 
of  the  urine  for  about  an  hour  after  the  spasms  had  ceased.  Bloating 
occurred  in  about  half  the  sheep,  some  of  them  being  severely  bloated. 
Before  death  there  was  a  period  of  quiet,  during  which  the  animal 
showed  few  signs  of  life  except  breathing. 

Treatment. 

The  only  treatment  that  has  proven  of  any  value  in  human  beings 
who  have  been  poisoned  by  water  hemlock  is  to  produce  vomiting  before 
a  fatal  dose  has  been  absorbed.  There  is  no  known  specific  antidote. 
To  produce  vomiting  is  usually  impossible  or  impractical  in  either 
cattle,  horses,  or  sheep.  The  poison  acts  so  quickly  that  there  is  little 
time  for  any  treatment,  and  after  the  symptoms  appear  the  animal  is 
so  excitable  that  any  treatment  would  be  difficult  to  apply. 

Method  of  Preventing  or  Reducing  Losses. 

The  water  hemlock  has  such  a  limited  distribution  that  can  easily 
be  grubbed  out  from  pastures  where  it  is  causing  losses.  The  cost  of 
a  poisoned  steer  would  pay  for  grubbing  several  acres.  In  grubbing 
it  does  not  appear  to  be  necessary  to  remove  the  entire  root ;  as  experi- 
ments seem  to  show  that  the  plant  dies  if  the  rootstock,  the  heavy 
tuberous  underground  base  of  the  stem,  is  removed.  It  seems  that  if 
the  rootstock  is  even  badly  mutilated  it  will  die  and  decay. 

After  the  plants  have  been  grubbed  they  should  not  be  left  in  the 
field  but  should  be  removed  to  where  stock  cannot  get  at  them,  and 
where  they  can  later  be  burned.  On  the  range  they  may  be  put  in  a 
hole,  a  fire  built  over  them  and  the  hole  afterwards  refilled.  Great 
care  must  be  taken  not  to  leave  any  roots  on  the  surface  of  the  ground, 
or  the  danger  of  poisoning  will  be  increased. 


CONCLUSIONS    CONCERNING    POISON    PARSNIP   (WATER    HEMLOCK) 

(1)  It  is  highly  poisonous  to  cattle,  sheep,  and  horses. 

(2)  The  tops  are  deadly  in  the  early  spring,  but  as  they  grow  larger 
they  cease  to  be  poisonous. 

(3)  The  older  tops  are  not  poisonous. 

(4)  Two  ounces,  -J  of  a  pound,  or  more  of  the  old  tubers  (roots)  are 
sufficient  to  kill  ordinary  range  ewes  or  to  make  them  sick. 

(5)  Ten  to  twelve  ounces,  about  f  of  a  pound,  of  the  old  tubers  will 
usually  prove  fatal  to  fully  matured  cows. 

(6)  A  dose  of  |  pound  to  one  pound  of  the  old  tubers  will  kill  a  horse. 

(7)  The  young  tubers  are  much  less  poisonous  than  the  old  ones, 
for  it  takes  from  two  to  four  times  as  much  of  the  new  tubers  to  kill 
an  animal. 

(8)  Water  hemlock  tubers  shipped  to  Reno  from  Nebraska  were  much 
less  poisonous  than  the  tubers  found  growing  in  Nevada. 

(9)  For  sheep  it  takes  from  16  to  75  minutes  for  symptoms  to 
appear.     In  the  cow  it  takes  about  an  hour  and  in  horses  about  45 
minutes. 

(10)  There  is  no  known  remedy. 

(11)  Drying  does  not  immediately  destroy  the  poisonous  principle  in 
the  plant.    One-half  ounce  of  dried  tubers  killed  a  mature  ewe. 

(12)  The  poison  parsnip  is  easily  removed  from  fields  by  grubbing. 
Great  care  must  be  taken  to  dispose  of  all  the  tubers,  so  that  live  stock 
cannot  get  any  chance  to  eat  them. 

(13)  Most  of  the  year  only  the  tubers  (roots)  are  poisonous.    In  the 
early  spring  the  young  leaves  are  almost,  if  not  quite,  as  poisonous  as 
the  tubers.    This  is  the  time  when  the  danger  is  greatest. 


SECTION    II 

Technical  Information  Concerning  the  Poison  Parsnip 
(Water  Hemlock) 

This  section  is  not  intended  for  use  by  farmers  and  stockmen.  The 
information  included  is  intended  primarily  for  chemists  and  veteri- 
narians. 


23 


THE    ACTIVE    POISONOUS    PRINCIPLE    OF    CICUTA 

Chemical  researches  have  been  made,  both  in  this  country  and 
abroad,  on  various  members  of  the  genus  Cicuta,  all  species  of  which 
are  probably  poisonous.  When  the  rootstocks  of  Cicuta  are  cut  or 
broken  open  there  is  an  exudation  of  a  yellowish,  aromatic  oily  mate- 
rial which  in  a  few  moments  begins  to  darken  to  a  reddish-brown  color. 
(See  Bulletin  81,  Nevada  Experiment  Station.)  This  yellowish  exu- 
date  is  the  poisonous  principle  of  the  root  and  it  may  be  also  seen  in 
the  lower  portions  of  the  stems  to  a  lesser  extent.  This  poisonous  prin- 
ciple of  Cicuta  has  been  the  subject  of  researches  by  a  number  of  experi- 
menters and  a  fair  idea  is  to  be  had  concerning  its  nature. 

In  order  to  obtain  the  poison  in  a  state  pure  enough  for  most  experi- 
mental work  the  fresh  tubers  may  be  reduced  to  a  pulp  and  extracted 
with  ether,  in  which  the  cicutoxin  (the  name  given  to  the  active  prin- 
ciple) dissolves.  Removal  of  the  moisture  and  ether  leaves  the  cicu- 
toxin in  the  pure  state.  In  addition  to  ether  it  will  also  dissolve  in 
alcohol,  methanol,  acetone,  and  chloroform.  It  is  only  slightly  soluble 
in  benzene,  carbon  tetrachloride,  and  petroleum  ether ;  and  is  insoluble 
in  water,  glycerine,  and  aniline. 

A  method  for  the  purification  of  the  poison  has  been  devised  which 
is  based  on  its  relative  solubility  in  alcohol  and  petroleum  ether,  the 
resulting  product  differing  but  little  in  purity  from  that  prepared  by 
the  method  first  mentioned.  The  chemical  formula  of  the  substance 
was  found  by  Dr.  C.  A.  Jacobson  of  the  Nevada  Station  to  be  C19H2603. 
In  extracting  the  green  tubers  with  ether  it  was  found  that  cicutoxin 
could  be  obtained  in  a  quantity  of  from  0.3  to  0.4  per  cent  of  the  weight 
of  the  tubers  used. 

When  prepared  in  the  pure  condition  cicutoxin  is  a  viscous  yellowish 
liquid  which  changes  spontaneously  into  a  semisolid  body  of  a  ruby-red 
to  reddish-brown  color.  It  has  the  characteristic  odor  of  the  poison 
parsnip  and  a  very  persistent  bitter  taste.  When  it  is  prepared  by 
dissolving  in  alcohol  and  precipitating  by  means  of  petroleum  ether 
it  is  obtained  in  a  noncrystalline  solid  which  melts  to  a  sirupy  mass 
when  heated  to  20°.  A  greater  increase  in  temperature  causes  a  loss 
in  toxicity  and  differences  have  apparently  been  observed  in  the  sub- 
stance obtained  from  plans  in  the  warmer  and  cooler  parts  of  the 
year. 

Experiments  with  the  rootstocks  of  the  plant  or  the  pure  poison  as 
obtained  and  administered  by  mouth  show  that  it  is  a  narcotic  cramp 
poison,  the  symptoms  of  which  in  the  lower  animals  are  like  those  in 
man  except  for  being  less  marked. 


Gaylord  Bros. 

Makers- 
Syracuse,  N.  V. 

PAT.  JAN.  21 ,1908 


48768 


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